Not Applicable.
Not Applicable.
The present invention relates generally to systems and methods for calibrating a thermocouple sensor. More specifically, the present invention relates to systems and methods for testing a thermocouple sensor used for testing integrated circuits.
Thermal control is a critical consideration in any microelectronics design process. One problem relating to thermal control is device failure. Studies have shown that element-related functional failures exhibit a strong relationship to operating temperature. For example, a 10-20 degree Celsius increase in chip temperature may double the element failure rate under some conditions. Another problem related to thermal control is the variability of the package temperature and corresponding variability in performance. Thermal designs seek to reduce the temperature variations within the package for consistent and reliable performance. For example, complementary metal-oxide semiconductor (CMOS) circuit speed is dependent on temperature. Thus, an increase or decrease in temperature may affect cycle times or timing margins.
The thermal characteristics of an integrated circuit, such as a microprocessor, must be tested repeatedly, both during the design phase and during manufacturing. One such testing device includes a test pad, a test control circuit, a movable armature, and a thermal head coupled to the armature. An integrated circuit to be tested is placed on the test pad. The test pad includes conductors which electrically couple contacts on the integrated circuit with the test control circuit. The moveable armature moves downward and brings a thermocouple sensor on the thermal head in contact with the packaging of the integrated circuit. The thermal head provides controlled temperatures to the integrated circuit while monitoring the temperature of the integrated circuit through the thermocouple sensor.
The accuracy of the thermocouple sensor is very important in this testing operation. Therefore, the thermocouple sensor is calibrated when the sensor is first used, and thereafter during preventive maintenance, to ensure the accuracy of the sensor during integrated circuit testing.
Calibration of the thermocouple sensor is a tedious process because the sensor must be dismounted from the thermal head. This requires unscrewing multiple screws to unclamp the thermocouple sensor, removing an aluminum clamp using a tweezers, and pulling the thermocouple wire out of the thermal head-all without damaging the thermocouple sensor. Thereafter, the sensor is sent to a calibration laboratory for calibration. After calibrating the sensor, it must be re-mounted to the thermal head. The entire calibration process can take 1 to 2 days to complete, which results in unacceptably long downtime for the testing device. The removal and re-mounting of the thermocouple sensor also requires skilled labor, thereby increasing overhead costs.
Accordingly, there is a need for a simple and yet effective system and method for calibrating a thermocouple sensor. Further, there is a need for a system and method for calibrating a thermocouple sensor that does not result in significant down time for the testing device. Further still, there is a need for a system and method for calibrating a thermocouple sensor without removing it from the thermal head. Further still, there is a need for reducing human finger and wrist fatigue when calibrating a thermocouple sensor.
According to an exemplary embodiment, a jig assembly for use in calibrating a thermocouple sensor includes a conductive member, a holder, and a fastener. The conductive member has a recess configured to receive a test wire and a test surface configured for thermal contact with the thermocouple sensor. The holder is adapted to receive the conductive member. The fastener is coupleable to the holder, wherein the holder and fastener form a recess configured to receive the test wire.
According to another exemplary embodiment, a method of calibrating a thermocouple sensor on a test device is provided. The test device has a test pad. The method includes placing a jig on a test pad. The jig includes a base portion, a conductive portion, and a test wire coupled to the conductive portion. The method further includes bringing the thermocouple sensor in thermal contact with the conductive portion. The method further includes performing a calibration routine on the thermocouple sensor.
According to yet another exemplary embodiment, a system for calibrating a thermocouple sensor coupled to a test device includes a means for sensing the temperature of the thermocouple sensor and a means for positioning the means for sensing on a test pad of the test device.